Stamenović Dimitrije, Liang Zhuangli, Chen Jianxin, Wang Ning
Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA.
J Appl Physiol (1985). 2002 Apr;92(4):1443-50. doi: 10.1152/japplphysiol.00782.2001.
We investigated the effect of the cytoskeletal prestress (P) on the elastic and frictional properties of cultured human airway smooth muscle cells during oscillatory loading; P is preexisting tensile stress in the actin cytoskeleton generated by the cell contractile apparatus. We oscillated (0.1 Hz, 6 Pa peak to peak) small ferromagnetic beads bound to integrin receptors and computed the storage (elastic) modulus (G') and the loss (frictional) modulus (G") from the applied torque and the corresponding bead rotation. All measurements were done at baseline and after cells were treated with graded doses of either histamine (0.1, 1, 10 microM) or isoproterenol (0.01, 0.1, 1, 10 microM). Values for P for these concentrations were taken from a previous study (Wang et al., Am J Physiol Cell Physiol, in press). It was found that G' and G", as well as P, increased/decreased with increasing doses of histamine/isoproterenol. Both G' and G" exhibited linear dependences on P: G'(Pa) = 0.20P + 82 and G"(Pa) = 0.05P + 32. The dependence of G' on P is consistent with our previous findings and with the behavior of stress-supported structures. The dependence of G" on P is a novel finding. It could be attributed to a variety of mechanisms. Some of those mechanisms are discussed in detail. We concluded that, in addition to the central mechanisms by which stress-supported structures develop mechanical stresses, other mechanisms might need to be invoked to fully explain the observed dependence of the cell mechanical properties on the state of cell contractility.
我们研究了细胞骨架预应力（P）对培养的人气道平滑肌细胞在振荡加载过程中弹性和摩擦特性的影响；P是由细胞收缩装置在肌动蛋白细胞骨架中预先存在的拉伸应力。我们使结合到整合素受体上的小铁磁珠振荡（0.1赫兹，峰峰值6帕斯卡），并根据施加的扭矩和相应的珠子旋转计算储能（弹性）模量（G'）和损耗（摩擦）模量（G''）。所有测量均在基线时以及用不同剂量的组胺（0.1、1、10微摩尔）或异丙肾上腺素（0.01、0.1、1、10微摩尔）处理细胞后进行。这些浓度下的P值取自先前的一项研究（Wang等人，《美国生理学杂志：细胞生理学》，即将发表）。结果发现，G'和G''以及P随组胺/异丙肾上腺素剂量的增加而增加/减少。G'和G''均表现出对P的线性依赖性：G'（帕斯卡）= 0.20P + 82，G''（帕斯卡）= 0.05P + 32。G'对P的依赖性与我们先前的发现以及应力支撑结构的行为一致。G''对P的依赖性是一个新发现。它可能归因于多种机制。其中一些机制将详细讨论。我们得出结论，除了应力支撑结构产生机械应力的核心机制外，可能还需要调用其他机制来充分解释观察到的细胞力学特性对细胞收缩状态的依赖性。
